Preheat oven to 350 degrees F (175 degrees C).

Place garlic cloves in a small baking dish. Drizzle with olive oil, cover, and bake 45 minutes, or until golden brown.

Bring a large pot of lightly salted water to boil. Add potatoes, and cook until tender but firm. Drain, and transfer to a large mixing bowl.

Place roasted garlic, milk, Parmesan cheese, and butter into the bowl with the potatoes. Season with salt and pepper. Beat to desired consistency with an electric mixer.